Tiltrotor aircraft having a downwardly tiltable aft rotor

Patent metadata

Field	Value
Publication number	US-10676188-B2
Application number	US-201715724649-A
Country	US
Kind code	B2
Filing date	Oct 4, 2017
Priority date	Oct 4, 2017
Publication date	Jun 9, 2020
Grant date	Jun 9, 2020

Abstract

A tiltrotor aircraft has a vertical takeoff and landing flight mode and a forward flight mode. The tiltrotor aircraft includes a longitudinally extending fuselage with a wing extending laterally therefrom having oppositely disposed wing tips distal from the fuselage. Tip booms respectively extend longitudinally from the wing tips. Forward rotors are coupled to the forward ends of the tip booms. The forward rotors are reversibly tiltable between a vertical lift orientation, wherein the forward rotors are above the tip booms, and a forward thrust orientation, wherein the forward rotors are forward of the tip booms. An aft rotor is coupled to the aft end of the fuselage. The aft rotor is reversibly tiltable between a vertical lift orientation, wherein the aft rotor is below the fuselage, and a forward thrust orientation, wherein the aft rotor is aft of the fuselage.

First claim

What is claimed is:

1. A tiltrotor aircraft having a vertical takeoff and landing flight mode and a forward flight mode, the aircraft comprising:
a longitudinally extending fuselage having an aft end;
a wing extending laterally from the fuselage having first and second oppositely disposed wing tips distal from the fuselage;
first and second tip booms respectively extending longitudinally from the first and second wing tips, the first and second tip booms each having forward and aft ends;
first and second forward rotors respectively coupled to the forward ends of the first and second tip booms, the first and second forward rotors reversibly tiltable between a vertical lift orientation, wherein the first and second forward rotors are above the respective first and second tip booms, and a forward thrust orientation, wherein the first and second forward rotors are forward of the respective first and second tip booms; and
an aft rotor coupled to the aft end of the fuselage, the aft rotor reversibly tiltable between a vertical lift orientation, wherein the aft rotor is below the fuselage, and a forward thrust orientation, wherein the aft rotor is aft of the fuselage.

2. The tiltrotor aircraft as recited in claim 1 wherein the forward rotors are counter rotated to control yaw in the vertical takeoff and landing flight mode.

3. The tiltrotor aircraft as recited in claim 1 wherein the forward rotors are counter rotated and the aft rotor is torque offset to control yaw in the vertical takeoff and landing flight mode.

4. The tiltrotor aircraft as recited in claim 1 wherein the aft rotor is torque offset to control yaw in the vertical takeoff and landing flight mode.

5. The tiltrotor aircraft as recited in claim 1 wherein the wing further comprises at least one flaperon.

6. The tiltrotor aircraft as recited in claim 1 wherein the forward rotors further comprise folding rotor blades operable to reduce drag in the forward flight mode.

7. The tiltrotor aircraft as recited in claim 1 wherein the aft rotor further comprises fixed pitch rotor blades.

8. The tiltrotor aircraft as recited in claim 1 further comprising a flight control system operably associated with the forward rotors and the aft rotor, the flight control system operable to independently control each of the forward and aft rotors including transitions between the vertical lift and the forward thrust orientations.

9. The tiltrotor aircraft as recited in claim 8 wherein the flight control system commands operation of the forward and aft rotors responsive to at least one of onboard pilot flight control, remote flight control, autonomous flight control and combinations thereof.

10. The tiltrotor aircraft as recited in claim 1 wherein the forward rotors are common rotated and the aft rotor is counter rotated to control yaw in the vertical takeoff and landing flight mode.

11. The tiltrotor aircraft as recited in claim 10 wherein each of the forward rotors is smaller than the aft rotor.

12. The tiltrotor aircraft as recited in claim 10 wherein each of the forward rotors has a lesser pitch than the aft rotor.

13. The tiltrotor aircraft as recited in claim 1 further comprising a power system including at least one electric motor operably associated with each of the rotors and an electric energy source.

14. The tiltrotor aircraft as recited in claim 13 wherein the electric energy source further comprises at least one battery.

15. The tiltrotor aircraft as recited in claim 13 wherein the electric energy source further comprises at least one internal combustion engine and at least one electric generator.

16. The tiltrotor aircraft as recited in claim 1 further comprising first and second tail assemblies respectively coupled to the aft ends of the first and second tip booms, the first and second tail assemblies operating in an upwash in the forward flight mode.

17. The tiltrotor aircraft as recited in claim 16 wherein the first and second tail assemblies operate in a dynamic pressure ratio of between 1.0 and 1.3 in the forward flight mode.

18. The tiltrotor aircraft as recited in claim 16 wherein the tail assemblies further comprise vertical and horizontal stabilizers.

19. The tiltrotor aircraft as recited in claim 16 wherein each tail assembly further comprises a rudder and elevator.

20. A tiltrotor aircraft having a vertical takeoff and landing flight mode and a forward flight mode, the aircraft comprising:
a longitudinally extending fuselage having an aft end;
a wing extending laterally from the fuselage having first and second oppositely disposed wing tips distal from the fuselage;
first and second tip booms respectively extending longitudinally from the first and second wing tips, the first and second tip booms each having forward and aft ends;
first and second forward rotors respectively coupled to the forward ends of the first and second tip booms, the first and second forward rotors reversibly tiltable between a vertical lift orientation, wherein the first and second forward rotors are above the respective first and second tip booms, and a forward thrust orientation, wherein the first and second forward rotors are forward of the respective first and second tip booms;
first and second tail assemblies respectively coupled to the aft ends of the first and second tip booms, the first and second tail assemblies operating in an upwash in the forward flight mode;
an aft rotor coupled to the aft end of the fuselage, the aft rotor reversibly tiltable between a vertical lift orientation, wherein the aft rotor is below the fuselage, and a forward thrust orientation, wherein the aft rotor is aft of the fuselage;
a flight control system operably associated with the forward rotors and the aft rotor, the flight control system operable to independently control each of the forward and aft rotors including transitions between the vertical lift and the forward thrust orientations; and
a power system including at least one electric motor operably associated with each of the rotors and an electric energy source.

Assignees

• Textron Innovations Inc

Inventors

• Campbell Kip Gregory

Classifications

• B64C27/26

  characterised by provision of fixed wings · CPC title

• B64C27/28

  with forward-propulsion propellers pivotable to act as lifting rotors · CPC title

• B64C27/52

  Tilting of rotor bodily relative to fuselage (of see-saw type construction B64C27/43) · CPC title

• B64C29/0033 Primary

  the propellers being tiltable relative to the fuselage · CPC title

• B64C15/12

  the power plant being tiltable · CPC title